Table 4.

Concordance of rectal chlamydia and urethral chlamydia between men in 406 partnerships in which both men did not have symptoms of urethritis or proctitis

	Urethra negative	Urethra positive	Total number of tests	Urethral chlamydia positivity % (95% CI)
Rectum negative	767	10	777	1.3 (0.6 to 2.4)
Rectum positive	27	8	35	22.8 (10.4 to 40.1)
Total number of tests	794	18	812	2.2 (1.3 to 3.5)
Rectal chlamydia positivity % (95% CI)	3.4 (2.3 to 4.9)	44.4 (21.5 to 69.2)	4.3 (3.0 to 5.9)

(McNemar’s test p = 0.005)

Each man is represented twice: once as a urethra and once as a rectum